Tool-steel alloy.



UNITED STATES PATENT OFFICE.

IRAIDGLYIEFE FURNESS, F JENKINTOWN, AND RICHARD H. PATCH, OF PHTLADELPHIA,

PENNSYLVANIA, ASSIGNORS TO THE MIDVALE STEEL COMPANY, OF PHILADEL- PHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

TOOL-STEEL ALLOY.

No Drawing.

Tocll whom it may concern:

Be it known that we, RADCLYFFE Forums and RICHARD H. PATCH, citizens of the United States, residing, respectively, at J enkintown, county of Montgomery, State of Pennsylvania, and Philadelphia, county of Philadelphia, State of Pennsylvania, have invented a new and useful Improvement in much more uniformly as cutting tools than do the known molybdenum tool steels.

The following is an example of a preferred composition of an alloy embodying our invention: chromium 4.0 per cent., molybdenum 8.0 per cent., vanadium 1.5 per cent., cobalt 5.0 per cent. This is a typical composition and one which careful experiment has shown to give excellent results.

The steel should contain about .65 per cent. carbon, the proportion of which should not exceed 1 per cent. The steel may contain the usual small percentages of natural alloys or impurities, such as manganese, silicon, titanium, phosphorus and sulfur. The precentage of vanadium, may vary up to 2.5 per cent.; the cobalt should not be less than two per cent. and should not ex- Specification of Letters Patent.

Patented Dec. 5, 1916.

Application filed December 14, 1915. Serial No. 66,840.

ceed 20 per cent., the chromium may vary within a range of 2.}- to 5 per cent., and the molybdenum within a range of from four to eleven per cent. The vanadium may be omitted. The efficiency of the alloy is, however, sufliciently increased by its addition to pay for such addition; but except in degree, the addition of vanadium does not change the essential properties or characteristics of the alloy.

Having now fully described our invention, what we claim and desire to protect by Letters Patent is:

1. A high speed tool steel containing chromium, molybdenum between four and eleven per cent. and cobalt.

2. A high speed tool steel containing the following ingredients in the proportions specified: chromium 2.5 to 5 per cent., molybdenum at to 11 per cent., and cobalt 2 to 20 per cent,

1 A high speed tool steel containing the following ingredients in the proportions specified: carbon less than one per cent.,

chromium 2.5 to 5 per cent., molybdenum 4 to 11 per cent., and cobalt 2 to 20 per cent.

4. A high speed tool steel containing the following ingredients in approximately'the proportions specified: carbon less than one per cent., chromium about A per cent., molybdenum about 8 per cent., and cobalt about 5 per cent.

In testimony of which invention, we have hereunto set our hands, at Philadelphia, on this first day ofDecember, 1915. A

RADOLYFFE FURNESS. RICHARD H. PATCH. Witnesses:

Jo's. ENTWISLE,

JAMES THoMPsoN. 

